JPS6121652Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a shock absorber for a check valve, and more specifically, the valve body fluttering (vibration) caused by a change in flow when the closing speed is slow and the valve is fully opened.
This relates to a shock absorber for a check valve.

Conventional check valves have a valve stem that protrudes outside the valve box, and a shock absorber is connected outside the valve box, so the structure is complex and large, requiring a large installation space, making them expensive as well. However, because the buffer fluid used was a different oil from the pipe fluid, there were problems such as the trouble of replacing the oil and the fact that it smeared the floor.

The object of this invention is to provide a shock absorber for a check valve that solves the above-mentioned conventional problems.

In order to achieve the above object, the check valve shock absorbing device of this invention is characterized by having the following configuration. That is, a valve stem having a valve body swingably supported in the bearing part is supported on a bearing part provided on one side of the valve box, and a first chevron having a fan-shaped cross section is attached to the tip end of the valve stem in the bearing part. A second chevron portion having a fan-shaped cross section having substantially the same shape as the first chevron portion is located within the bearing portion and is fixed to the bearing cover so as to face the first chevron portion, and the first chevron portion and the second chevron portion A buffer space is formed in the bearing part by the valve body, and a first communication passage is formed on one side of the second chevron part to communicate the space with the communication pipe provided in the bearing part cover when the valve body is fully opened. A second communication passage communicating between the space and the communication pipe is formed on the other side of the second angular part, and a notch is formed to communicate with the first communication passage when the first angular part moves from fully open to fully closed. The notch is provided in the first chevron portion, and when the first chevron portion approaches one side or the other side of the second chevron portion, the notch is fitted into the notch and acts as a flow rate regulating valve provided on the bearing portion or the bearing portion cover. The gap is narrow and the other gaps are wide, and the communication pipe is provided with a check valve that allows fluid to flow from the second communication path to the first communication path, and an on-off valve that removes air from the fluid. is provided.

The above action is as follows. If some kind of backflow occurs when the valve body is fully open, the valve body swings in the closing direction, and the valve stem rotates accordingly, causing the first chevron portion of the valve stem to move toward one side of the second chevron portion. swaying to
A buffer space formed by one side of the first chevron portion and the second chevron portion is compressed. At this time, from the first communication path to the second
Fluid does not flow into the communication passage due to the check valve, and fluid only flows through the gap between the notch that communicates with the first communication passage and the flow rate adjustment valve fitted into this notch, and the fluid only flows through this gap. flows into the buffer space formed by the other side surface of the first chevron portion and the second chevron portion. As a result, throttling resistance occurs in the flow of fluid, and the valve body swings in the closing direction due to the gap setting between the notch and the flow rate adjustment valve, which is gentle near full open, becomes slightly faster near intermediate opening, and then swings again near full close. It is buffered to make it more gradual. Next, when a forward flow occurs when the valve body is fully closed, the valve body swings in the opening direction, and the valve stem accordingly rotates in the opposite direction, causing the first chevron portion of the valve stem to move to the first chevron. It swings in the direction of the other side surface of the two chevron portions, compressing the buffer space formed by the other side surfaces of the first chevron portion and the second chevron portion. At this time, the fluid flows from the second communicating path to the first communicating path via the communicating pipe without being blocked by the check valve as described above. Therefore, the valve body is not prevented from swinging in the opening direction, and is quickly brought to the open position.

This idea has the following unique effects. In other words, since the swinging of the valve body in the closing direction is damped as described above, water hammer, which occurs when the valve body closes rapidly, does not occur, and there is no risk of swinging or damaging the pipe or valve. On the other hand, the buffer is large near fully open and fully closed, and becomes small near intermediate opening, so
Even if water hammer is to be prevented, the valve body can be oscillated at a relatively high speed near the intermediate opening, and the three-stage oscillation speed allows extremely smooth operation of the valve body. Obtainable. In addition, since the communication pipe has an on-off valve,
When filling the buffer space with fluid (liquid), by opening the on-off valve, the air in the fluid that would be an obstacle to the buffering effect can be removed to the outside, ensuring that the buffering effect is performed only with air-free fluid. Not only is the structure simple and compact, it requires less installation space and is less expensive, but it also uses the fluid inside the valve as a buffer fluid, which eliminates the need for oil, which was previously used. There are no troublesome problems such as having to replace the floor or staining the floor.

Examples of this invention will be described below.

In Figures 1 to 4, 1 is a valve body, 2 is a valve body fixed to valve stems 3 and 3' eccentrically supported by the valve body 1, and when the flow is in the forward direction, the valve port 4 is It is opened, fluid flows in through the opening 5 and flows out through the opening 6 through the valve port 4, and when there is no flow or reverse flow, the valve body valve seat 7 is brought into close contact with the valve body valve seat 8 to close the valve port 4. It is something. A counterweight 9 is fixed to the valve stem 3' via a lever 10.

The valve stem 3 is supported via a bush 12 by a bearing part 11 provided in the valve box 1, and a chevron part 13 having a fan-shaped cross section is formed at the tip of the valve stem 3 inside the bearing part 11. . This chevron portion 13 is formed on a cover 15 fixed to the bearing portion 11 via a packing 14, and has a fan-shaped cross section having the same shape as the chevron portion 13.
It is facing 6. Reference numeral 17 denotes a V-shaped or U-shaped packing, which is located closer to the valve body than the bottom surface 19 of the angled portion 16 and which connects the bushing 12 and the bearing portion 11 to the angled portion 1.
Between the distance rings 18 that are pivotally supported on the 3 sides,
It is held in a clamping manner with the V-shaped or U-shaped opening surface facing the distance ring 18 side. Therefore, this packing 17 allows the pressure fluid to pass from the valve body 2 side to the cover 15 side, but prevents the pressure fluid from passing from the cover 15 side to the valve body 2 side. This is because when pressure is applied from the valve body 2 side, force acts in the direction of closing the lip of the opening, that is, in the direction of the lip moving away from the bearing part 11 of the valve stem 3, and when pressure is applied from the cover 15 side, the lip opens. This is because the force acting in such a direction increases the force of contact between the lip and the valve stem 3 and bearing portion 11.

The opposing relationship between the chevron 13 formed at the tip of the valve stem 3 and the chevron 16 formed at the end of the cover 15 will be explained as follows.

The bottom surface 19 of the chevron portion 13 and the end surface 2 of the chevron portion 16
0′, the end surface 19′ of the chevron portion 13, and the bottom surface 20 of the chevron portion 16 face each other with a slight gap,
Moreover, the side surface 19'' of the chevron 13, the side surface 20'' of the chevron 16, the side surface 19 of the chevron 13, the side surface 20 of the chevron 16, and the distance ring 18.
Buffer chambers A and B are formed in the hollow portion formed by the buffer chambers A and B, which increase and decrease the gap angle in proportion to the rotation angle β of the valve stem 3 that rotates as the valve body 2 opens and closes.
The maximum clearance angle α of the A and B chambers is formed to match the fully open angle β of the valve body 2, and in the case shown in the third figure, the clearance angle of the A chamber is 0 and the clearance angle of the B chamber is the maximum. The swing angle of the valve body 2 corresponding to this indicates the maximum β degree (fully open), and in the case of Fig. 4, the gap angle of chamber A is the maximum gap angle of α degree and the gap angle of chamber B indicates a minimum of 0 degrees, and the corresponding swing angle β of the valve body 2 indicates a minimum of 0 degrees (fully closed).

Reference numeral 21 denotes communicating passages 22 and 22' formed in the longitudinal direction at the base of both sides 20'' and 20 of the chevron portion 16.
A gate valve 23 and a check valve 24 are connected to this communication pipe 21. The gate valve 23 is normally closed, and when the air between the opposing portions of the chevron portion 13 and the chevron portion 16 is to be removed, the opposing portion is filled with pipe fluid (liquid) and the air from this portion is removed. will be opened to Further, the check valve 24 is formed so as to close the flow of fluid from the communication passage 22' toward the communication passage 22, that is, from the buffer chamber B to the buffer chamber A.

Reference numeral 25 denotes a flow rate adjustment valve, which is screwed onto the cover 15, and includes a step-like notch 26 having an arcuate wall provided on the end face 19' of the chevron portion 13, and this flow rate adjustment valve 25.
The gap is adjusted so that the gap becomes narrower when the valve body 2 is in the fully closed and fully open positions. In order to narrow this gap, in this embodiment, the axis of the flow rate regulating valve 25 is formed to be eccentric with respect to the axis of the circular arc wall of the notch 26, and the side surface 19'' of the angular portion 13 and the angular portion 16 The area where the side surface 20'' comes into contact (when the valve body 2 is fully open) and the chevron portion 1
The gap is formed so that the gap becomes narrow near where the side surface 19 of the valve body 3 and the side surface 20 of the chevron portion 16 come into contact (when the valve body 2 is fully closed). 27 is Rocknut, 28
is attached to the flow rate regulating valve 25 with a gasket.

The embodiment of this invention is composed of the above-mentioned members, and their functions will be explained as follows.
First, to explain the route of the fluid to the buffer chamber etc., if the gate valve 23 is opened when the fluid starts to flow into the main pipe of the valve box 1, the fluid in the main pipe will flow through the gap between the bush 12 and the valve stem 3. , passes through the seal 17 and the gap between the distance ring 18 and the valve stem 3 to the buffer chambers A and B, the notch 26, and the communication passages 22 and 2.
Enter 2'. Therefore, the air in each of the gaps in the buffer chambers A, B, etc. is discharged from the gate valve 23, and the gate valve 23 is closed when these gaps are filled with the fluid in the main pipe. In this state, when the flow is in the forward direction, the valve body 2 is in the position shown by the solid line in the second figure (fully open), and fluid flows in from the opening 5, passes through the valve port 4, and flows out from the opening. The chevron portion 13 of the valve body 2 and the chevron portion 1 of the cover 15 when the valve body 2 is fully open
6, the side surface 19'' of the chevron portion 13 and the side surface 20'' of the chevron portion 16 are in contact with each other, as shown in the third diagram.
The side surface 20'' plays the role of positioning the maximum opening degree of the valve body 2, and the buffer chamber A is at the minimum and the buffer chamber B is at the maximum.When the valve body 2 is in the fully open position in this way, When there is a fluctuation in the flow, the valve body 2 vibrates and swings in the closing direction due to the influence of the flow, and the side surface 19 of the chevron portion 13 of the valve stem 3 that is integrated with the valve 2 rotates accordingly.
If the action of compressing the buffer chamber B occurs,
Since the flow from the buffer chamber B to the buffer chamber A is closed by the check valve 24 of the connecting pipe 21, the flow is limited to the gap between the flow rate adjustment valve 25 and the notch 26, and flows through the notch 26 to the buffer chamber. Since this gap is narrow, the fluid flowing out to A creates a flow restriction resistance, and the swinging of the valve body 2 in the closing direction is damped.

Next, when backflow occurs for some reason, the valve body 3 begins to swing in the closing direction, but in this case as well, the flow through the communication pipe 21 from the buffer chamber B to the buffer chamber A is closed by the check valve 24. Therefore, the fluid flows only through the gap between the notch 26 and the flow rate regulating valve 25, and the closing speed is
Corresponding to the gap between the valve 6 and the flow rate regulating valve 25, the valve closes slowly when it is fully open as shown in the third figure, becomes slightly faster in the middle, and slowly closes when it is close to fully closed as shown in the fourth figure.

Further, when a forward flow occurs when the valve body 2 is closed, the valve body 2 starts to swing in the opening direction, but at this time, the flow from the buffer chamber A to the buffer chamber B passes through the communication pipe 21. Since it is not closed by the stop valve 24,
Since it passes through the communication pipe 21, the swinging of the valve body 2 is not hindered, and the valve body 2 quickly becomes the open position.

A second embodiment of this invention is shown in FIGS. 5, 6 and 7, in which:
A side surface 19'' and a circumferential groove 29 that becomes shallow near the side surface 19 are provided on the circumferential wall of the chevron portion 13 in the first embodiment, and a flow rate regulating valve 25' that fits the circumferential groove 29 is installed in the bearing portion 11 and the distance ring 18. The gap between the circumferential groove 29 and the flow rate regulating valve 25' is narrowed when the valve body is fully open (Fig. 6) and fully closed (Fig. 7), as in the first embodiment. The action and effect are the same.

In the above embodiment of this invention, the valve stem 3 and the bearing part 1
V-shaped or U-shaped packing 1 between the seals
7 is used, and the pressure fluid from the valve body 2 side can pass to the cover side, but it has a structure that does not allow it to pass from the cover side to the valve body 2 side. Alternatively, another communication pipe may be provided which is equipped with a gate valve that communicates between the gate valve 23 and check valve 24 of the communication pipe 21 and the valve box 1. 18 is abolished, and the chevron parts 13, 16 and the bearing part 1 are replaced.
Buffer chambers A and B may be formed by one inner wall.
Further, this invention is applicable not only to the eccentric butterfly type check valve in the embodiment but also to a butterfly type valve swing type check valve.

[Brief explanation of the drawing]

Figures 1 to 4 show the first embodiment of this invention.
5, 6, and 7 show the second embodiment; FIG. 1 is a partially sectional front view of the main part; FIG. 2 is a cross-sectional view taken along the - line in FIG. 1; Figure 1 -
4 is an enlarged cross-sectional view of FIG. 3, FIG. 5 is a cross-sectional view of the main parts, FIG. 6 is a cross-sectional view of FIG. It is a diagram. 1: Valve box, 2: Valve body, 3: Valve stem, 11: Bearing, 12: Bush, 13: Chevron, 14: Packing, 15: Cover, 16: Chevron, 17: Packing, 18: Distance ring, 19,1
9′: bottom and end surfaces of the chevron portion 13, 20, 20′: bottom and end surfaces of the chevron portion 16, 19″, 19: side surfaces on both sides of the chevron portion 13, 20″, 20: chevron portion 16
21: communication pipe, 22, 22': communication path, 23: gate valve, 24: check valve, 25: flow rate adjustment valve, 26: notch, A, B: buffer chamber.

Claims (1)

[Scope of utility model registration request] A valve stem having a valve body swingably supported within the bearing is supported on a bearing provided on one side of the valve box, and a first chevron having a fan-shaped cross section is provided at the tip of the bearing. A second chevron having a fan-shaped cross section that is approximately the same shape as the first chevron is formed.
A chevron portion is disposed within the bearing portion and is fixed to the bearing cover so as to face the first chevron portion, and a buffer space is formed within the bearing portion by the first and second chevron portions, and when the valve body is fully opened, a buffer space is formed in the bearing portion. A first communication passage that communicates the communication pipe provided in the bearing cover is formed on one side of the second angular part, and a second communication passage that communicates the space and the communication pipe when fully closed is formed on the second angular part. The first chevron is formed on the other side, and the first chevron is provided with a notch that communicates with the first communicating part when the first chevron moves from fully open to fully closed. When approaching one side or the other side, the gap between the notch and the flow rate regulating valve provided on the bearing section or the bearing section cover is narrow, and the other side is wide. A shock absorbing device for a check valve, characterized in that the communication pipe is provided with a check valve that allows fluid to flow from the second communication path to the first communication path, and an on-off valve that removes air from the fluid.